The first three chapters of this book will analyse the three main ways in which the Welsh came to Ireland during this period: to serve in the military, to work in the administration, and to settle in the plantations. Together they will seek to quantify and explore the nature of the Welsh presence in Ireland, which will enable an exploration of Welsh community and identity in Ireland in the final two chapters. This chapter will address the Welsh role in the English army in Ireland. The military formed the bulk of the English and Welsh presence in Ireland between 1558 and 1641. Before 1603 the overwhelming majority of English and Welsh in Ireland were soldiers. Even after this point, and despite the arrival of thousands of settlers, soldiers remained a large and influential part of the New English community. Here I will assess the extent of Welsh involvement as soldiers and officers in the English army in Ireland. In both cases it is demonstrated that there was a significant Welsh presence in the military. The chapter will also explore the type of Welshmen levied for Irish service and develop an understanding of the origins, backgrounds and motivations of Welsh officers. It is necessary to establish who the Welsh in the military were because they will be central to the rest of the study.